Raney metal catalysts containing iron have been reported, but these catalysts showed poor results in hydrogenation reactions. For example, it was reported in L. Kh. Freidlin, A. A. Balandin, and T. A. Sladkova in Dokl. Akad. Nauk SSSR, 112, 880 (1957) that attempted hydrogenation of the dinitrile of terephthalic acid in the presence of Raney iron as catalyst gave no isolatable diamine. Later, in L. Kh. Freidlin and T. A. Sladkova, Russ. Chem. Rev., 33, 319 (1964) it was stated "Raney iron has a low catalytic activity" and "activity of metallic catalysts towards the reduction of dinitriles decreases in the sequence: Pt,Pd&gt;Ni&gt;Co&gt;Fe,Cu." In R. L. Augustine, Catalytic Hydrogenation, Dekker, N.Y., 1965, p. 32, it is stated "Raney copper and Raney iron do not have much to offer the synthetic organic chemist, as only a few reactions are reported to be affected by them".
U.S. Pat. No. 2,257,814 describes hydrogenation of dinitriles in the presence of mild-acting catalysts prepared by leaching an alloy of aluminum, iron and cobalt with an aqueous alkaline solution to provide the catalyst which contains 5 to 10% by weight of cobalt and 95 to 90% by weight of iron. The use of third metal in catalyst compositions taught in this patent is discouraged.
U.S. Pat. Nos. 4,826,799 and 4,895,994, each directed to catalysts made by the Raney process and pelletized in a matrix of polymer and plasticizer, make a broad disclosure of Raney process alloys consisting of 45-75 weight % Al and 25-55% of a conventional Raney process metal, e.g., Ni, Co, Cu, or Fe, or mixture of these. These Raney catalysts may be promoted by, e.g., Cr, Mo, Pt, Rh, Ru, Os and Pd, typically at about 2 weight % of total metal.
U.S. Pat. No. 5,151,543 reports a process for selective hydrogenation of aliphatic dinitriles to aminonitriles under low pressure with high yield using a Raney-type catalyst selected from the group consisting of Raney nickel, Raney cobalt, and Raney nickel promoted with metals or metal oxides selected from Group VIB or promoted with ferrous metals of Group VIII of the Periodic Table. Thus, in this catalyst iron, if used at all, would be present in only low concentrations.
It is an object of the present invention to provide a Raney iron catalyst which is effective in the low pressure catalytic hydrogenation of a variety of organic compounds, particularly a catalyst effective for the hydrogenation of aliphatic organic nitrites to organic primary amines.